Motor-vehicle



H. D. CHURCH.

MOTOR VEHICLE.

yMmc/mon FILED' JAN. 13. 1919.

Patented 1, 1921.

,To all 'whom t may concern:

UNITED STATES PATENT OFFICE.

HAROLD D. CHURCH, .OF DETROIT, MICHIGAN, ASSIGNOR TO PACKARD MOTOR CAR COMPANY, 0F DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

Mo'roR-vEHrcLE.

Specication of Letters Patent.

' Patented Mar. 1, 1921.

'Application filed January 13, 1919. Serial No. 270,974.

Be it known that I', HAROLD D. CHURCH, a citizen of the United States, and resident of Detroit, Wayne county, State of Michigan, have invented certain new and useful Improvements in Motor-Vehicles, of which the following is a specification.

This invention relates to motor vehicles. It has particular relation to hydraulic brakes for such vehicles.

One object of the invention is to provide a brake of effective construction capable of producing a powerful pressure under a stroke ofdtllie usual length applied to the brake pe a Another object of the invention is to provide a brake in which `the first part of the movement of the brake pedal or other operating member is relatively rapid so as to quickly take upl the clearances between the various brake parts, and in which increased power may be obtained during the remain- 1(ser of the movement of the operating mem- Another object of the invention is to provide a construction obtaining the above relatively quick initial movement of the brake, pedal and the. slower movement and relatively greater power during the latter part ofthe pedal stroke, in which the respective parts accomplishing this differential action are embodied in a power element of simple construction. f

Another object of the invention is to generally improve the construction and operation of mechanisms of the above class.

The invention is embodied in preferable form in the construction and arrangementhereinafter described and illustrated in the accompanying drawings.

In these drawings- Figure 1 is a vertical sectional view showing the hydraulic power elements of the braking mechanism; and

Fig. 2 is a side elevation showing 'said elements applied to a motor vehicle in connection with a brake, and the connected parts between said brake and the power elements.

Fig. 3 is a section ofthe large power cylinder showing the pistons in brake operating position. A

Referring to the drawings-10 indicates a brake pedal or other operating member to whichpower may be applied to effect the operation of the power increasing elements intermediate said member and the brakes.'

' mentindependently of the combined rod and piston member 13. These two pistons are movable 1n a cylinder 15 which is filled with 011 or other liquid and with which said pistons coperate to form the main power in-. lcreasing element.

A spring 16 is mounted on the piston rod 13 between one face 'of the piston 14 and a nut 17 threaded on said rod 13.

' In the inward movement of the member 13 under the pressure applied thereto by the pedal, the pressure will be transmitted through the spring 16 so as to cause the main' piston 14 to be` also moved inward conjointly with the member 13 until the resistance due to the increasing 'friction o'f the brake parts and thelopposlng pressure of the fluid is reater than the force ofV the sprmg 16A w ereupon the pressure of the spring against the nut on the rod 13A will' The outer end of the' cylinder 15 com. .municates by conduit 18 ywith a secondary hydraulic power element comprising a cylinder 19 in which apiston 2() is mounted for reciprocation and-so as to receive pressure from the mconnng fluld. The plston 201s of less-cross sectional area than the piston 14 but of greater cross sectional area than the piston member 13. The piston 20 is carried by rod 21, the outer end of which is pivoted to an arm .22. which is fixed on a rocking shaft 23, from which project arms 24 to which are pivoted brake rods 25 caring at their ends suitable operating members 26 for brakes 27.

In the operation of the device, when pressure is applied to the pedal or similar 0peratin member, the piston 13 will be carried inwar and' owing to the pressure thereof against the spring 16 the main piston 14 willI sectional area of the movement of the parts connected to the brake, and thus serving to quickly take up the clearances between these parts. As the resistance increases the operation of the lpower applying element 14 has a tendency to be slowed up and thereupon the pressure of the spring between the piston 14 and piston 13 being overcome, the latter piston will be moved forward independently of piston 14 and transmit further pressure to the fluid, such pressure being increased in force by the relatively greater area of the pressure receiving piston 20 with respect to said piston 13.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In combination with a brake for motor vehicles., foot or hand controlled actuating means, a hydraulic power line between said actuating means and said brake, including a pair of cylinders of different cross areas and a piston element of differential area in one of said cylinders adapted to vary in respect to its moving face as the resistance in the line increases from a large area to a smaller area, and the means of direct communication between the two cylinders. 2. In combination with a brake for motor vehicles, operating means therefor, foot or 40 hand controlled actuating means, a hydraulic power line including a pair of cylinders to direct communication. betweenv said operating means and said brake, and a differential hydraulic power applying piston in said line operable with a rapid initial movement and a succeeding heavy pressure movement.

3. In combination with a brake for motor vehicles, an operating member, a hydraulic power element between said parts having a fluid containing cylinder and a piston therein, and a piston rod movable independently of the piston and connections between said rod and member` and a second cylinder havative movement thereof, and a second cylinder and piston having communication with the first cylinder.

5. In combination with a brake for motor vehicles, an operating member, a' fluid containing cylinder, a piston therein, a supplemental piston of less cross sectional area movable relatively to the first pist-on, means to cause said pistons to move together on the operation of said member, and permitting the relative movement of said pistons when a predetermined resistance is encountered by the main piston, and means of connection between the smaller piston and the operating member. .p

6. In combination with a brake for motor vehicles, an operating member, a fluid containing cylinder between the brake and said member, a piston movable therein, a smaller piston in said cylinder capable of movement relatively to the first piston and constituting a piston rod for the latter, a spring between a part of' the piston rod and said larger piston and operating connections for the brakes subject to the pressure in the fluid cylinder.

l7. In combination with a brake for motor vehicles, an operating member, a fluid containing cylinder, a fluid line, a pressure transmitting piston lin said cylinder, a second cylinder with a pressure receiving piston, and means vofcommunication between the second piston and the brake, a supplemental piston mounted in the first cylinder and movable relatively thereto, and of less cross sectional area than either of the other pistons, means of connection between said supplemental piston and said operating member and means to move said first piston by said supplemental piston, said means permitting a relative movement of said'pistons upon resistance to the main piston of a predetermined amount.

In testimony whereof I affix my signature.

HAROLD D. CHURCH.

".- 111; is;y hereby certified that in I Jetters Patent No. 1,369,915, grante'd March 1l v19.2.1, upon the application of `Harold D. Churchfof Detroit, Michigan, for an v lmprovement 1n Motor-Vehlcles, an error appears ln-the prmted speclcatwn reqiiiring correctionv as follows: Page 2, line 41, claim 2, for the Word to read in; andthe-t the said Letters Patent should be read with this correction therein tht the same moy conforrn to the record lof the 'cavse in the Patent Office. n

Signed and sealed this 12th day of April, A. D., 1921.

[SEAL] 1 T. RBERTYSON,

Commissioner of Patents. 

